The invention relates to an integrated-circuit card having inhibition means. The card can be of the contactless or contact type.
The invention relates particularly to an integrated-circuit card of the contactless type, of the type in which a card body in the form of a sheet carries an integrated circuit and an antenna by means of which the integrated circuit is able to communicate remotely with a reception terminal, and of the type in which the antenna, which lies in the plane of the card body, is produced in the form of a winding, over several turns, of a conductive track.
In a particularly usual application, the integrated-circuit cards, also referred to as smart cards, are used as a means of paying for a service. At each use of the corresponding service, at least one unit of value is decremented in an initial stock of units of value loaded in the memory of the smart card. Such applications are found for example in telephone cards and photocopier cards.
Thus the users purchase a card which is initially provided in memory with a given number of units of value corresponding to the maximum credit.
In the majority of applications in which the integrated-circuit card is used as a payment means, the cards used are of the contact card type in which the card has conductive tracks which are connected to the electronic module or integrated circuit, and which are intended to afford an electrical connection between the card and the reception terminal.
In this case, it is fairly easy to give a guarantee to the user purchasing a card assumed to include the maximum number of units of value, quite simply by surrounding the card with a sealed envelope, for example in the form of a xe2x80x9ccellophanexe2x80x9d packaging, which prevents any electrical contact with the conductive tracks.
Such a solution is however not satisfactory when it is a case of a contactless card with which the exchanges of information take place at a distance, for example by means of radiofrequency waves. This is because this exchange of information can then take place through the cellophane envelope, which can therefore no longer serve as a guarantee of the prior non-use of the card.
The purpose of the invention is therefore to propose a novel design of an integrated-circuit card, or smart card, in which means are provided for preventing any fraudulent use of the card before first use thereof by an authorised user.
For this purpose, the invention proposes an integrated-circuit card of the type described above, characterised in that at least one conductive connecting bridge is provided, which connects at least two turns of the antenna in order to reduce the inductance thereof, and in that the connecting bridge lies partly in a rupture zone of the card body which is intended to be broken at the time of the first use of the card in order to break the connecting bridge.
According to other characteristics of the invention:
the antenna is connected to the integrated circuit by means of two terminals and, before being broken, the connecting bridge connects the two terminals;
the connecting bridge connects an internal turn to an external turn of the antenna;
the card has several connecting bridges which each connect two consecutive turns of the winding;
the card has several rupture zones each intended to allow the breaking of at least one connecting bridge;
the connecting bridge is produced simultaneously with the winding;
the connecting bridge is produced in the form of a member attached with respect to the winding; and
the connecting bridge straddles the turns of the winding, and an insulant is provided which is interposed between the connecting bridge and the turns.